Seasonal Variations of Hydro-Biological Conditions in Mangro areas of Vembanad Lake along Cherrayi-Kumbalam sector

Abstract- The present investigation was carried out for determining the various hydro-biological parameters of mangrove patches of Vembanad lake along Cherrayi – Kumbalam sector. For the period of September 2015 to July 2016 covering all the four seasons of southwest monsoon, post monsoon, northeast monsoon and pre-monsoon. The study has been carried out at three selected mangrove stations. The physico-chemical parameters like water temperature, transparency, salinity, pH, dissolved oxygen and nutrients were analyzed. The water temperature, salinity and alkalinity were maximum at pre monsoon period. Dissolved oxygen value is high during southwest monsoon period and water pH was alkaline during southwest monsoon season. The lowest values were seen for nitrate-N and phosphate-P during the study period. Statistical analysis of the seasonal variation of physico-chemical parameters were done by using one way ANOVA. Major zooplanktons identified during the study period was copepods, rotifers, crustacean larvae and cladocerans. Among the shellfishes Feneropenaeus indicus was the important species. 30 species of finfishes were collected during the study period in which the order Perciformes contributed the maximum diversity.